Frequencies for first 10,000 rows of payself variable in nhamcsopd2011 dataset :

   Expected |
  source of |
  payment - |
   Self-pay |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,024       90.24       90.24
        Yes |        976        9.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016